_ Git - rust-lightning/blob - lightning/src/offers/refund.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! Data structures and encoding for refunds.
  11 //!
  12 //! A [`Refund`] is an "offer for money" and is typically constructed by a merchant and presented
  13 //! directly to the customer. The recipient responds with a [`Bolt12Invoice`] to be paid.
  14 //!
  15 //! This is an [`InvoiceRequest`] produced *not* in response to an [`Offer`].
  16 //!
  17 //! [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
  18 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
  19 //! [`Offer`]: crate::offers::offer::Offer
  20 //!
  21 //! # Example
  22 //!
  23 //! ```
  24 //! extern crate bitcoin;
  25 //! extern crate core;
  26 //! extern crate lightning;
  27 //!
  28 //! use core::convert::TryFrom;
  29 //! use core::time::Duration;
  30 //!
  31 //! use bitcoin::network::constants::Network;
  32 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  33 //! use lightning::offers::parse::Bolt12ParseError;
  34 //! use lightning::offers::refund::{Refund, RefundBuilder};
  35 //! use lightning::util::ser::{Readable, Writeable};
  36 //!
  37 //! # use lightning::blinded_path::BlindedPath;
  38 //! # #[cfg(feature = "std")]
  39 //! # use std::time::SystemTime;
  40 //! #
  41 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  42 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  43 //! #
  44 //! # #[cfg(feature = "std")]
  45 //! # fn build() -> Result<(), Bolt12ParseError> {
  46 //! let secp_ctx = Secp256k1::new();
  47 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  48 //! let pubkey = PublicKey::from(keys);
  49 //!
  50 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  51 //! let refund = RefundBuilder::new("coffee, large".to_string(), vec![1; 32], pubkey, 20_000)?
  52 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  53 //!     .issuer("Foo Bar".to_string())
  54 //!     .path(create_blinded_path())
  55 //!     .path(create_another_blinded_path())
  56 //!     .chain(Network::Bitcoin)
  57 //!     .payer_note("refund for order #12345".to_string())
  58 //!     .build()?;
  59 //!
  60 //! // Encode as a bech32 string for use in a QR code.
  61 //! let encoded_refund = refund.to_string();
  62 //!
  63 //! // Parse from a bech32 string after scanning from a QR code.
  64 //! let refund = encoded_refund.parse::<Refund>()?;
  65 //!
  66 //! // Encode refund as raw bytes.
  67 //! let mut bytes = Vec::new();
  68 //! refund.write(&mut bytes).unwrap();
  69 //!
  70 //! // Decode raw bytes into an refund.
  71 //! let refund = Refund::try_from(bytes)?;
  72 //! # Ok(())
  73 //! # }
  74 //! ```
  75 //!
  76 //! # Note
  77 //!
  78 //! If constructing a [`Refund`] for use with a [`ChannelManager`], use
  79 //! [`ChannelManager::create_refund_builder`] instead of [`RefundBuilder::new`].
  80 //!
  81 //! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  82 //! [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
  83
  84 use bitcoin::blockdata::constants::ChainHash;
  85 use bitcoin::network::constants::Network;
  86 use bitcoin::secp256k1::{PublicKey, Secp256k1, self};
  87 use core::hash::{Hash, Hasher};
  88 use core::ops::Deref;
  89 use core::str::FromStr;
  90 use core::time::Duration;
  91 use crate::sign::EntropySource;
  92 use crate::io;
  93 use crate::blinded_path::BlindedPath;
  94 use crate::ln::PaymentHash;
  95 use crate::ln::channelmanager::PaymentId;
  96 use crate::ln::features::InvoiceRequestFeatures;
  97 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  98 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
  99 use crate::offers::invoice::BlindedPayInfo;
 100 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
 101 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
 102 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
 103 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
 104 use crate::offers::signer::{Metadata, MetadataMaterial, self};
 105 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
 106 use crate::util::string::PrintableString;
 107
 108 #[cfg(not(c_bindings))]
 109 use {
 110         crate::offers::invoice::{DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder},
 111 };
 112 #[cfg(c_bindings)]
 113 use {
 114         crate::offers::invoice::{InvoiceWithDerivedSigningPubkeyBuilder, InvoiceWithExplicitSigningPubkeyBuilder},
 115 };
 116
 117 #[allow(unused_imports)]
 118 use crate::prelude::*;
 119
 120 #[cfg(feature = "std")]
 121 use std::time::SystemTime;
 122
 123 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Refund ~~~~~";
 124
 125 /// Builds a [`Refund`] for the "offer for money" flow.
 126 ///
 127 /// See [module-level documentation] for usage.
 128 ///
 129 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 130 ///
 131 /// [module-level documentation]: self
 132 pub struct RefundBuilder<'a, T: secp256k1::Signing> {
 133         refund: RefundContents,
 134         secp_ctx: Option<&'a Secp256k1<T>>,
 135 }
 136
 137 /// Builds a [`Refund`] for the "offer for money" flow.
 138 ///
 139 /// See [module-level documentation] for usage.
 140 ///
 141 /// [module-level documentation]: self
 142 #[cfg(c_bindings)]
 143 pub struct RefundMaybeWithDerivedMetadataBuilder<'a> {
 144         refund: RefundContents,
 145         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 146 }
 147
 148 macro_rules! refund_explicit_metadata_builder_methods { () => {
 149         /// Creates a new builder for a refund using the [`Refund::payer_id`] for the public node id to
 150         /// send to if no [`Refund::paths`] are set. Otherwise, it may be a transient pubkey.
 151         ///
 152         /// Additionally, sets the required [`Refund::description`], [`Refund::payer_metadata`], and
 153         /// [`Refund::amount_msats`].
 154         ///
 155         /// # Note
 156         ///
 157         /// If constructing a [`Refund`] for use with a [`ChannelManager`], use
 158         /// [`ChannelManager::create_refund_builder`] instead of [`RefundBuilder::new`].
 159         ///
 160         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 161         /// [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
 162         pub fn new(
 163                 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
 164         ) -> Result<Self, Bolt12SemanticError> {
 165                 if amount_msats > MAX_VALUE_MSAT {
 166                         return Err(Bolt12SemanticError::InvalidAmount);
 167                 }
 168
 169                 let metadata = Metadata::Bytes(metadata);
 170                 Ok(Self {
 171                         refund: RefundContents {
 172                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
 173                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
 174                                 quantity: None, payer_id, payer_note: None,
 175                         },
 176                         secp_ctx: None,
 177                 })
 178         }
 179 } }
 180
 181 macro_rules! refund_builder_methods { (
 182         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr, $secp_context: ty $(, $self_mut: tt)?
 183 ) => {
 184         /// Similar to [`RefundBuilder::new`] except, if [`RefundBuilder::path`] is called, the payer id
 185         /// is derived from the given [`ExpandedKey`] and nonce. This provides sender privacy by using a
 186         /// different payer id for each refund, assuming a different nonce is used.  Otherwise, the
 187         /// provided `node_id` is used for the payer id.
 188         ///
 189         /// Also, sets the metadata when [`RefundBuilder::build`] is called such that it can be used to
 190         /// verify that an [`InvoiceRequest`] was produced for the refund given an [`ExpandedKey`].
 191         ///
 192         /// The `payment_id` is encrypted in the metadata and should be unique. This ensures that only
 193         /// one invoice will be paid for the refund and that payments can be uniquely identified.
 194         ///
 195         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 196         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 197         pub fn deriving_payer_id<ES: Deref>(
 198                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 199                 secp_ctx: &'a Secp256k1<$secp_context>, amount_msats: u64, payment_id: PaymentId
 200         ) -> Result<Self, Bolt12SemanticError> where ES::Target: EntropySource {
 201                 if amount_msats > MAX_VALUE_MSAT {
 202                         return Err(Bolt12SemanticError::InvalidAmount);
 203                 }
 204
 205                 let nonce = Nonce::from_entropy_source(entropy_source);
 206                 let payment_id = Some(payment_id);
 207                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, payment_id);
 208                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 209                 Ok(Self {
 210                         refund: RefundContents {
 211                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
 212                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
 213                                 quantity: None, payer_id: node_id, payer_note: None,
 214                         },
 215                         secp_ctx: Some(secp_ctx),
 216                 })
 217         }
 218
 219         /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 220         /// already passed is valid and can be checked for using [`Refund::is_expired`].
 221         ///
 222         /// Successive calls to this method will override the previous setting.
 223         pub fn absolute_expiry($($self_mut)* $self: $self_type, absolute_expiry: Duration) -> $return_type {
 224                 $self.refund.absolute_expiry = Some(absolute_expiry);
 225                 $return_value
 226         }
 227
 228         /// Sets the [`Refund::issuer`].
 229         ///
 230         /// Successive calls to this method will override the previous setting.
 231         pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
 232                 $self.refund.issuer = Some(issuer);
 233                 $return_value
 234         }
 235
 236         /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
 237         /// by private channels or if [`Refund::payer_id`] is not a public node id.
 238         ///
 239         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 240         /// adding duplicate paths.
 241         pub fn path($($self_mut)* $self: $self_type, path: BlindedPath) -> $return_type {
 242                 $self.refund.paths.get_or_insert_with(Vec::new).push(path);
 243                 $return_value
 244         }
 245
 246         /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
 247         /// called, [`Network::Bitcoin`] is assumed.
 248         ///
 249         /// Successive calls to this method will override the previous setting.
 250         pub fn chain($self: $self_type, network: Network) -> $return_type {
 251                 $self.chain_hash(ChainHash::using_genesis_block(network))
 252         }
 253
 254         /// Sets the [`Refund::chain`] of the given [`ChainHash`] for paying an invoice. If not called,
 255         /// [`Network::Bitcoin`] is assumed.
 256         ///
 257         /// Successive calls to this method will override the previous setting.
 258         pub(crate) fn chain_hash($($self_mut)* $self: $self_type, chain: ChainHash) -> $return_type {
 259                 $self.refund.chain = Some(chain);
 260                 $return_value
 261         }
 262
 263         /// Sets [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
 264         /// when the refund pertains to a [`Bolt12Invoice`] that paid for more than one item from an
 265         /// [`Offer`] as specified by [`InvoiceRequest::quantity`].
 266         ///
 267         /// Successive calls to this method will override the previous setting.
 268         ///
 269         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 270         /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
 271         /// [`Offer`]: crate::offers::offer::Offer
 272         pub fn quantity($($self_mut)* $self: $self_type, quantity: u64) -> $return_type {
 273                 $self.refund.quantity = Some(quantity);
 274                 $return_value
 275         }
 276
 277         /// Sets the [`Refund::payer_note`].
 278         ///
 279         /// Successive calls to this method will override the previous setting.
 280         pub fn payer_note($($self_mut)* $self: $self_type, payer_note: String) -> $return_type {
 281                 $self.refund.payer_note = Some(payer_note);
 282                 $return_value
 283         }
 284
 285         /// Builds a [`Refund`] after checking for valid semantics.
 286         pub fn build($($self_mut)* $self: $self_type) -> Result<Refund, Bolt12SemanticError> {
 287                 if $self.refund.chain() == $self.refund.implied_chain() {
 288                         $self.refund.chain = None;
 289                 }
 290
 291                 // Create the metadata for stateless verification of a Bolt12Invoice.
 292                 if $self.refund.payer.0.has_derivation_material() {
 293                         let mut metadata = core::mem::take(&mut $self.refund.payer.0);
 294
 295                         if $self.refund.paths.is_none() {
 296                                 metadata = metadata.without_keys();
 297                         }
 298
 299                         let mut tlv_stream = $self.refund.as_tlv_stream();
 300                         tlv_stream.0.metadata = None;
 301                         if metadata.derives_payer_keys() {
 302                                 tlv_stream.2.payer_id = None;
 303                         }
 304
 305                         let (derived_metadata, keys) = metadata.derive_from(tlv_stream, $self.secp_ctx);
 306                         metadata = derived_metadata;
 307                         if let Some(keys) = keys {
 308                                 $self.refund.payer_id = keys.public_key();
 309                         }
 310
 311                         $self.refund.payer.0 = metadata;
 312                 }
 313
 314                 let mut bytes = Vec::new();
 315                 $self.refund.write(&mut bytes).unwrap();
 316
 317                 Ok(Refund {
 318                         bytes,
 319                         #[cfg(not(c_bindings))]
 320                         contents: $self.refund,
 321                         #[cfg(c_bindings)]
 322                         contents: $self.refund.clone(),
 323                 })
 324         }
 325 } }
 326
 327 #[cfg(test)]
 328 macro_rules! refund_builder_test_methods { (
 329         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 330 ) => {
 331         #[cfg_attr(c_bindings, allow(dead_code))]
 332         pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
 333                 $self.refund.paths = None;
 334                 $return_value
 335         }
 336
 337         #[cfg_attr(c_bindings, allow(dead_code))]
 338         fn features_unchecked($($self_mut)* $self: $self_type, features: InvoiceRequestFeatures) -> $return_type {
 339                 $self.refund.features = features;
 340                 $return_value
 341         }
 342 } }
 343
 344 impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
 345         refund_explicit_metadata_builder_methods!();
 346 }
 347
 348 impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
 349         refund_builder_methods!(self, Self, Self, self, T, mut);
 350
 351         #[cfg(test)]
 352         refund_builder_test_methods!(self, Self, Self, self, mut);
 353 }
 354
 355 #[cfg(all(c_bindings, not(test)))]
 356 impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
 357         refund_explicit_metadata_builder_methods!();
 358         refund_builder_methods!(self, &mut Self, (), (), secp256k1::All);
 359 }
 360
 361 #[cfg(all(c_bindings, test))]
 362 impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
 363         refund_explicit_metadata_builder_methods!();
 364         refund_builder_methods!(self, &mut Self, &mut Self, self, secp256k1::All);
 365         refund_builder_test_methods!(self, &mut Self, &mut Self, self);
 366 }
 367
 368 #[cfg(c_bindings)]
 369 impl<'a> From<RefundBuilder<'a, secp256k1::All>>
 370 for RefundMaybeWithDerivedMetadataBuilder<'a> {
 371         fn from(builder: RefundBuilder<'a, secp256k1::All>) -> Self {
 372                 let RefundBuilder { refund, secp_ctx } = builder;
 373
 374                 Self { refund, secp_ctx }
 375         }
 376 }
 377
 378 /// A `Refund` is a request to send an [`Bolt12Invoice`] without a preceding [`Offer`].
 379 ///
 380 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 381 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 382 /// bitcoin ATM.
 383 ///
 384 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 385 /// [`Offer`]: crate::offers::offer::Offer
 386 #[derive(Clone, Debug)]
 387 pub struct Refund {
 388         pub(super) bytes: Vec<u8>,
 389         pub(super) contents: RefundContents,
 390 }
 391
 392 /// The contents of a [`Refund`], which may be shared with an [`Bolt12Invoice`].
 393 ///
 394 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 395 #[derive(Clone, Debug)]
 396 #[cfg_attr(test, derive(PartialEq))]
 397 pub(super) struct RefundContents {
 398         payer: PayerContents,
 399         // offer fields
 400         description: String,
 401         absolute_expiry: Option<Duration>,
 402         issuer: Option<String>,
 403         paths: Option<Vec<BlindedPath>>,
 404         // invoice_request fields
 405         chain: Option<ChainHash>,
 406         amount_msats: u64,
 407         features: InvoiceRequestFeatures,
 408         quantity: Option<u64>,
 409         payer_id: PublicKey,
 410         payer_note: Option<String>,
 411 }
 412
 413 impl Refund {
 414         /// A complete description of the purpose of the refund. Intended to be displayed to the user
 415         /// but with the caveat that it has not been verified in any way.
 416         pub fn description(&self) -> PrintableString {
 417                 self.contents.description()
 418         }
 419
 420         /// Duration since the Unix epoch when an invoice should no longer be sent.
 421         ///
 422         /// If `None`, the refund does not expire.
 423         pub fn absolute_expiry(&self) -> Option<Duration> {
 424                 self.contents.absolute_expiry()
 425         }
 426
 427         /// Whether the refund has expired.
 428         #[cfg(feature = "std")]
 429         pub fn is_expired(&self) -> bool {
 430                 self.contents.is_expired()
 431         }
 432
 433         /// Whether the refund has expired given the duration since the Unix epoch.
 434         pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 435                 self.contents.is_expired_no_std(duration_since_epoch)
 436         }
 437
 438         /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
 439         /// displayed to the user but with the caveat that it has not been verified in any way.
 440         pub fn issuer(&self) -> Option<PrintableString> {
 441                 self.contents.issuer()
 442         }
 443
 444         /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
 445         /// privacy by obfuscating its node id.
 446         pub fn paths(&self) -> &[BlindedPath] {
 447                 self.contents.paths()
 448         }
 449
 450         /// An unpredictable series of bytes, typically containing information about the derivation of
 451         /// [`payer_id`].
 452         ///
 453         /// [`payer_id`]: Self::payer_id
 454         pub fn payer_metadata(&self) -> &[u8] {
 455                 self.contents.metadata()
 456         }
 457
 458         /// A chain that the refund is valid for.
 459         pub fn chain(&self) -> ChainHash {
 460                 self.contents.chain()
 461         }
 462
 463         /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
 464         ///
 465         /// [`chain`]: Self::chain
 466         pub fn amount_msats(&self) -> u64 {
 467                 self.contents.amount_msats()
 468         }
 469
 470         /// Features pertaining to requesting an invoice.
 471         pub fn features(&self) -> &InvoiceRequestFeatures {
 472                 &self.contents.features()
 473         }
 474
 475         /// The quantity of an item that refund is for.
 476         pub fn quantity(&self) -> Option<u64> {
 477                 self.contents.quantity()
 478         }
 479
 480         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 481         /// transient pubkey.
 482         ///
 483         /// [`paths`]: Self::paths
 484         pub fn payer_id(&self) -> PublicKey {
 485                 self.contents.payer_id()
 486         }
 487
 488         /// Payer provided note to include in the invoice.
 489         pub fn payer_note(&self) -> Option<PrintableString> {
 490                 self.contents.payer_note()
 491         }
 492 }
 493
 494 macro_rules! respond_with_explicit_signing_pubkey_methods { ($self: ident, $builder: ty) => {
 495         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields and using the
 496         /// [`Duration`] since [`std::time::SystemTime::UNIX_EPOCH`] as the creation time.
 497         ///
 498         /// See [`Refund::respond_with_no_std`] for further details where the aforementioned creation
 499         /// time is used for the `created_at` parameter.
 500         ///
 501         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 502         ///
 503         /// [`Duration`]: core::time::Duration
 504         #[cfg(feature = "std")]
 505         pub fn respond_with(
 506                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 507                 signing_pubkey: PublicKey,
 508         ) -> Result<$builder, Bolt12SemanticError> {
 509                 let created_at = std::time::SystemTime::now()
 510                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 511                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 512
 513                 $self.respond_with_no_std(payment_paths, payment_hash, signing_pubkey, created_at)
 514         }
 515
 516         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields.
 517         ///
 518         /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
 519         /// `created_at`, which is used to set [`Bolt12Invoice::created_at`]. Useful for `no-std` builds
 520         /// where [`std::time::SystemTime`] is not available.
 521         ///
 522         /// The caller is expected to remember the preimage of `payment_hash` in order to
 523         /// claim a payment for the invoice.
 524         ///
 525         /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
 526         /// offer, which does have a `signing_pubkey`.
 527         ///
 528         /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
 529         /// must contain one or more elements ordered from most-preferred to least-preferred, if there's
 530         /// a preference. Note, however, that any privacy is lost if a public node id is used for
 531         /// `signing_pubkey`.
 532         ///
 533         /// Errors if the request contains unknown required features.
 534         ///
 535         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 536         ///
 537         /// [`Bolt12Invoice::created_at`]: crate::offers::invoice::Bolt12Invoice::created_at
 538         pub fn respond_with_no_std(
 539                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 540                 signing_pubkey: PublicKey, created_at: Duration
 541         ) -> Result<$builder, Bolt12SemanticError> {
 542                 if $self.features().requires_unknown_bits() {
 543                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 544                 }
 545
 546                 <$builder>::for_refund($self, payment_paths, created_at, payment_hash, signing_pubkey)
 547         }
 548 } }
 549
 550 macro_rules! respond_with_derived_signing_pubkey_methods { ($self: ident, $builder: ty) => {
 551         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
 552         /// derived signing keys to sign the [`Bolt12Invoice`].
 553         ///
 554         /// See [`Refund::respond_with`] for further details.
 555         ///
 556         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 557         ///
 558         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 559         #[cfg(feature = "std")]
 560         pub fn respond_using_derived_keys<ES: Deref>(
 561                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 562                 expanded_key: &ExpandedKey, entropy_source: ES
 563         ) -> Result<$builder, Bolt12SemanticError>
 564         where
 565                 ES::Target: EntropySource,
 566         {
 567                 let created_at = std::time::SystemTime::now()
 568                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 569                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 570
 571                 $self.respond_using_derived_keys_no_std(
 572                         payment_paths, payment_hash, created_at, expanded_key, entropy_source
 573                 )
 574         }
 575
 576         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
 577         /// derived signing keys to sign the [`Bolt12Invoice`].
 578         ///
 579         /// See [`Refund::respond_with_no_std`] for further details.
 580         ///
 581         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 582         ///
 583         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 584         pub fn respond_using_derived_keys_no_std<ES: Deref>(
 585                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 586                 created_at: core::time::Duration, expanded_key: &ExpandedKey, entropy_source: ES
 587         ) -> Result<$builder, Bolt12SemanticError>
 588         where
 589                 ES::Target: EntropySource,
 590         {
 591                 if $self.features().requires_unknown_bits() {
 592                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 593                 }
 594
 595                 let nonce = Nonce::from_entropy_source(entropy_source);
 596                 let keys = signer::derive_keys(nonce, expanded_key);
 597                 <$builder>::for_refund_using_keys($self, payment_paths, created_at, payment_hash, keys)
 598         }
 599 } }
 600
 601 #[cfg(not(c_bindings))]
 602 impl Refund {
 603         respond_with_explicit_signing_pubkey_methods!(self, InvoiceBuilder<ExplicitSigningPubkey>);
 604         respond_with_derived_signing_pubkey_methods!(self, InvoiceBuilder<DerivedSigningPubkey>);
 605 }
 606
 607 #[cfg(c_bindings)]
 608 impl Refund {
 609         respond_with_explicit_signing_pubkey_methods!(self, InvoiceWithExplicitSigningPubkeyBuilder);
 610         respond_with_derived_signing_pubkey_methods!(self, InvoiceWithDerivedSigningPubkeyBuilder);
 611 }
 612
 613 #[cfg(test)]
 614 impl Refund {
 615         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 616                 self.contents.as_tlv_stream()
 617         }
 618 }
 619
 620 impl AsRef<[u8]> for Refund {
 621         fn as_ref(&self) -> &[u8] {
 622                 &self.bytes
 623         }
 624 }
 625
 626 impl PartialEq for Refund {
 627         fn eq(&self, other: &Self) -> bool {
 628                 self.bytes.eq(&other.bytes)
 629         }
 630 }
 631
 632 impl Eq for Refund {}
 633
 634 impl Hash for Refund {
 635         fn hash<H: Hasher>(&self, state: &mut H) {
 636                 self.bytes.hash(state);
 637         }
 638 }
 639
 640 impl RefundContents {
 641         pub fn description(&self) -> PrintableString {
 642                 PrintableString(&self.description)
 643         }
 644
 645         pub fn absolute_expiry(&self) -> Option<Duration> {
 646                 self.absolute_expiry
 647         }
 648
 649         #[cfg(feature = "std")]
 650         pub(super) fn is_expired(&self) -> bool {
 651                 SystemTime::UNIX_EPOCH
 652                         .elapsed()
 653                         .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
 654                         .unwrap_or(false)
 655         }
 656
 657         pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 658                 self.absolute_expiry
 659                         .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
 660                         .unwrap_or(false)
 661         }
 662
 663         pub fn issuer(&self) -> Option<PrintableString> {
 664                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 665         }
 666
 667         pub fn paths(&self) -> &[BlindedPath] {
 668                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 669         }
 670
 671         pub(super) fn metadata(&self) -> &[u8] {
 672                 self.payer.0.as_bytes().map(|bytes| bytes.as_slice()).unwrap_or(&[])
 673         }
 674
 675         pub(super) fn chain(&self) -> ChainHash {
 676                 self.chain.unwrap_or_else(|| self.implied_chain())
 677         }
 678
 679         pub fn implied_chain(&self) -> ChainHash {
 680                 ChainHash::using_genesis_block(Network::Bitcoin)
 681         }
 682
 683         pub fn amount_msats(&self) -> u64 {
 684                 self.amount_msats
 685         }
 686
 687         /// Features pertaining to requesting an invoice.
 688         pub fn features(&self) -> &InvoiceRequestFeatures {
 689                 &self.features
 690         }
 691
 692         /// The quantity of an item that refund is for.
 693         pub fn quantity(&self) -> Option<u64> {
 694                 self.quantity
 695         }
 696
 697         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 698         /// transient pubkey.
 699         ///
 700         /// [`paths`]: Self::paths
 701         pub fn payer_id(&self) -> PublicKey {
 702                 self.payer_id
 703         }
 704
 705         /// Payer provided note to include in the invoice.
 706         pub fn payer_note(&self) -> Option<PrintableString> {
 707                 self.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 708         }
 709
 710         pub(super) fn derives_keys(&self) -> bool {
 711                 self.payer.0.derives_payer_keys()
 712         }
 713
 714         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 715                 let payer = PayerTlvStreamRef {
 716                         metadata: self.payer.0.as_bytes(),
 717                 };
 718
 719                 let offer = OfferTlvStreamRef {
 720                         chains: None,
 721                         metadata: None,
 722                         currency: None,
 723                         amount: None,
 724                         description: Some(&self.description),
 725                         features: None,
 726                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 727                         paths: self.paths.as_ref(),
 728                         issuer: self.issuer.as_ref(),
 729                         quantity_max: None,
 730                         node_id: None,
 731                 };
 732
 733                 let features = {
 734                         if self.features == InvoiceRequestFeatures::empty() { None }
 735                         else { Some(&self.features) }
 736                 };
 737
 738                 let invoice_request = InvoiceRequestTlvStreamRef {
 739                         chain: self.chain.as_ref(),
 740                         amount: Some(self.amount_msats),
 741                         features,
 742                         quantity: self.quantity,
 743                         payer_id: Some(&self.payer_id),
 744                         payer_note: self.payer_note.as_ref(),
 745                 };
 746
 747                 (payer, offer, invoice_request)
 748         }
 749 }
 750
 751 impl Writeable for Refund {
 752         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 753                 WithoutLength(&self.bytes).write(writer)
 754         }
 755 }
 756
 757 impl Writeable for RefundContents {
 758         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 759                 self.as_tlv_stream().write(writer)
 760         }
 761 }
 762
 763 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 764
 765 type RefundTlvStreamRef<'a> = (
 766         PayerTlvStreamRef<'a>,
 767         OfferTlvStreamRef<'a>,
 768         InvoiceRequestTlvStreamRef<'a>,
 769 );
 770
 771 impl SeekReadable for RefundTlvStream {
 772         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 773                 let payer = SeekReadable::read(r)?;
 774                 let offer = SeekReadable::read(r)?;
 775                 let invoice_request = SeekReadable::read(r)?;
 776
 777                 Ok((payer, offer, invoice_request))
 778         }
 779 }
 780
 781 impl Bech32Encode for Refund {
 782         const BECH32_HRP: &'static str = "lnr";
 783 }
 784
 785 impl FromStr for Refund {
 786         type Err = Bolt12ParseError;
 787
 788         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 789                 Refund::from_bech32_str(s)
 790         }
 791 }
 792
 793 impl TryFrom<Vec<u8>> for Refund {
 794         type Error = Bolt12ParseError;
 795
 796         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 797                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 798                 let ParsedMessage { bytes, tlv_stream } = refund;
 799                 let contents = RefundContents::try_from(tlv_stream)?;
 800
 801                 Ok(Refund { bytes, contents })
 802         }
 803 }
 804
 805 impl TryFrom<RefundTlvStream> for RefundContents {
 806         type Error = Bolt12SemanticError;
 807
 808         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 809                 let (
 810                         PayerTlvStream { metadata: payer_metadata },
 811                         OfferTlvStream {
 812                                 chains, metadata, currency, amount: offer_amount, description,
 813                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 814                         },
 815                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 816                 ) = tlv_stream;
 817
 818                 let payer = match payer_metadata {
 819                         None => return Err(Bolt12SemanticError::MissingPayerMetadata),
 820                         Some(metadata) => PayerContents(Metadata::Bytes(metadata)),
 821                 };
 822
 823                 if metadata.is_some() {
 824                         return Err(Bolt12SemanticError::UnexpectedMetadata);
 825                 }
 826
 827                 if chains.is_some() {
 828                         return Err(Bolt12SemanticError::UnexpectedChain);
 829                 }
 830
 831                 if currency.is_some() || offer_amount.is_some() {
 832                         return Err(Bolt12SemanticError::UnexpectedAmount);
 833                 }
 834
 835                 let description = match description {
 836                         None => return Err(Bolt12SemanticError::MissingDescription),
 837                         Some(description) => description,
 838                 };
 839
 840                 if offer_features.is_some() {
 841                         return Err(Bolt12SemanticError::UnexpectedFeatures);
 842                 }
 843
 844                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 845
 846                 if quantity_max.is_some() {
 847                         return Err(Bolt12SemanticError::UnexpectedQuantity);
 848                 }
 849
 850                 if node_id.is_some() {
 851                         return Err(Bolt12SemanticError::UnexpectedSigningPubkey);
 852                 }
 853
 854                 let amount_msats = match amount {
 855                         None => return Err(Bolt12SemanticError::MissingAmount),
 856                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 857                                 return Err(Bolt12SemanticError::InvalidAmount);
 858                         },
 859                         Some(amount_msats) => amount_msats,
 860                 };
 861
 862                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 863
 864                 let payer_id = match payer_id {
 865                         None => return Err(Bolt12SemanticError::MissingPayerId),
 866                         Some(payer_id) => payer_id,
 867                 };
 868
 869                 Ok(RefundContents {
 870                         payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
 871                         quantity, payer_id, payer_note,
 872                 })
 873         }
 874 }
 875
 876 impl core::fmt::Display for Refund {
 877         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 878                 self.fmt_bech32_str(f)
 879         }
 880 }
 881
 882 #[cfg(test)]
 883 mod tests {
 884         use super::{Refund, RefundTlvStreamRef};
 885         #[cfg(not(c_bindings))]
 886         use {
 887                 super::RefundBuilder,
 888         };
 889         #[cfg(c_bindings)]
 890         use {
 891                 super::RefundMaybeWithDerivedMetadataBuilder as RefundBuilder,
 892         };
 893
 894         use bitcoin::blockdata::constants::ChainHash;
 895         use bitcoin::network::constants::Network;
 896         use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
 897
 898         use core::time::Duration;
 899
 900         use crate::blinded_path::{BlindedHop, BlindedPath};
 901         use crate::sign::KeyMaterial;
 902         use crate::ln::channelmanager::PaymentId;
 903         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 904         use crate::ln::inbound_payment::ExpandedKey;
 905         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 906         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 907         use crate::offers::offer::OfferTlvStreamRef;
 908         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 909         use crate::offers::payer::PayerTlvStreamRef;
 910         use crate::offers::test_utils::*;
 911         use crate::util::ser::{BigSize, Writeable};
 912         use crate::util::string::PrintableString;
 913         use crate::prelude::*;
 914
 915         trait ToBytes {
 916                 fn to_bytes(&self) -> Vec<u8>;
 917         }
 918
 919         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 920                 fn to_bytes(&self) -> Vec<u8> {
 921                         let mut buffer = Vec::new();
 922                         self.write(&mut buffer).unwrap();
 923                         buffer
 924                 }
 925         }
 926
 927         #[test]
 928         fn builds_refund_with_defaults() {
 929                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 930                         .build().unwrap();
 931
 932                 let mut buffer = Vec::new();
 933                 refund.write(&mut buffer).unwrap();
 934
 935                 assert_eq!(refund.bytes, buffer.as_slice());
 936                 assert_eq!(refund.payer_metadata(), &[1; 32]);
 937                 assert_eq!(refund.description(), PrintableString("foo"));
 938                 assert_eq!(refund.absolute_expiry(), None);
 939                 #[cfg(feature = "std")]
 940                 assert!(!refund.is_expired());
 941                 assert_eq!(refund.paths(), &[]);
 942                 assert_eq!(refund.issuer(), None);
 943                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 944                 assert_eq!(refund.amount_msats(), 1000);
 945                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 946                 assert_eq!(refund.payer_id(), payer_pubkey());
 947                 assert_eq!(refund.payer_note(), None);
 948
 949                 assert_eq!(
 950                         refund.as_tlv_stream(),
 951                         (
 952                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 953                                 OfferTlvStreamRef {
 954                                         chains: None,
 955                                         metadata: None,
 956                                         currency: None,
 957                                         amount: None,
 958                                         description: Some(&String::from("foo")),
 959                                         features: None,
 960                                         absolute_expiry: None,
 961                                         paths: None,
 962                                         issuer: None,
 963                                         quantity_max: None,
 964                                         node_id: None,
 965                                 },
 966                                 InvoiceRequestTlvStreamRef {
 967                                         chain: None,
 968                                         amount: Some(1000),
 969                                         features: None,
 970                                         quantity: None,
 971                                         payer_id: Some(&payer_pubkey()),
 972                                         payer_note: None,
 973                                 },
 974                         ),
 975                 );
 976
 977                 if let Err(e) = Refund::try_from(buffer) {
 978                         panic!("error parsing refund: {:?}", e);
 979                 }
 980         }
 981
 982         #[test]
 983         fn fails_building_refund_with_invalid_amount() {
 984                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 985                         Ok(_) => panic!("expected error"),
 986                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
 987                 }
 988         }
 989
 990         #[test]
 991         fn builds_refund_with_metadata_derived() {
 992                 let desc = "foo".to_string();
 993                 let node_id = payer_pubkey();
 994                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 995                 let entropy = FixedEntropy {};
 996                 let secp_ctx = Secp256k1::new();
 997                 let payment_id = PaymentId([1; 32]);
 998
 999                 let refund = RefundBuilder
1000                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
1001                         .unwrap()
1002                         .build().unwrap();
1003                 assert_eq!(refund.payer_id(), node_id);
1004
1005                 // Fails verification with altered fields
1006                 let invoice = refund
1007                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1008                         .unwrap()
1009                         .build().unwrap()
1010                         .sign(recipient_sign).unwrap();
1011                 match invoice.verify(&expanded_key, &secp_ctx) {
1012                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
1013                         Err(()) => panic!("verification failed"),
1014                 }
1015
1016                 let mut tlv_stream = refund.as_tlv_stream();
1017                 tlv_stream.2.amount = Some(2000);
1018
1019                 let mut encoded_refund = Vec::new();
1020                 tlv_stream.write(&mut encoded_refund).unwrap();
1021
1022                 let invoice = Refund::try_from(encoded_refund).unwrap()
1023                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1024                         .unwrap()
1025                         .build().unwrap()
1026                         .sign(recipient_sign).unwrap();
1027                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1028
1029                 // Fails verification with altered metadata
1030                 let mut tlv_stream = refund.as_tlv_stream();
1031                 let metadata = tlv_stream.0.metadata.unwrap().iter().copied().rev().collect();
1032                 tlv_stream.0.metadata = Some(&metadata);
1033
1034                 let mut encoded_refund = Vec::new();
1035                 tlv_stream.write(&mut encoded_refund).unwrap();
1036
1037                 let invoice = Refund::try_from(encoded_refund).unwrap()
1038                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1039                         .unwrap()
1040                         .build().unwrap()
1041                         .sign(recipient_sign).unwrap();
1042                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1043         }
1044
1045         #[test]
1046         fn builds_refund_with_derived_payer_id() {
1047                 let desc = "foo".to_string();
1048                 let node_id = payer_pubkey();
1049                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1050                 let entropy = FixedEntropy {};
1051                 let secp_ctx = Secp256k1::new();
1052                 let payment_id = PaymentId([1; 32]);
1053
1054                 let blinded_path = BlindedPath {
1055                         introduction_node_id: pubkey(40),
1056                         blinding_point: pubkey(41),
1057                         blinded_hops: vec![
1058                                 BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1059                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1060                         ],
1061                 };
1062
1063                 let refund = RefundBuilder
1064                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
1065                         .unwrap()
1066                         .path(blinded_path)
1067                         .build().unwrap();
1068                 assert_ne!(refund.payer_id(), node_id);
1069
1070                 let invoice = refund
1071                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1072                         .unwrap()
1073                         .build().unwrap()
1074                         .sign(recipient_sign).unwrap();
1075                 match invoice.verify(&expanded_key, &secp_ctx) {
1076                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
1077                         Err(()) => panic!("verification failed"),
1078                 }
1079
1080                 // Fails verification with altered fields
1081                 let mut tlv_stream = refund.as_tlv_stream();
1082                 tlv_stream.2.amount = Some(2000);
1083
1084                 let mut encoded_refund = Vec::new();
1085                 tlv_stream.write(&mut encoded_refund).unwrap();
1086
1087                 let invoice = Refund::try_from(encoded_refund).unwrap()
1088                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1089                         .unwrap()
1090                         .build().unwrap()
1091                         .sign(recipient_sign).unwrap();
1092                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1093
1094                 // Fails verification with altered payer_id
1095                 let mut tlv_stream = refund.as_tlv_stream();
1096                 let payer_id = pubkey(1);
1097                 tlv_stream.2.payer_id = Some(&payer_id);
1098
1099                 let mut encoded_refund = Vec::new();
1100                 tlv_stream.write(&mut encoded_refund).unwrap();
1101
1102                 let invoice = Refund::try_from(encoded_refund).unwrap()
1103                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1104                         .unwrap()
1105                         .build().unwrap()
1106                         .sign(recipient_sign).unwrap();
1107                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1108         }
1109
1110         #[test]
1111         fn builds_refund_with_absolute_expiry() {
1112                 let future_expiry = Duration::from_secs(u64::max_value());
1113                 let past_expiry = Duration::from_secs(0);
1114                 let now = future_expiry - Duration::from_secs(1_000);
1115
1116                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1117                         .absolute_expiry(future_expiry)
1118                         .build()
1119                         .unwrap();
1120                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1121                 #[cfg(feature = "std")]
1122                 assert!(!refund.is_expired());
1123                 assert!(!refund.is_expired_no_std(now));
1124                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
1125                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
1126
1127                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1128                         .absolute_expiry(future_expiry)
1129                         .absolute_expiry(past_expiry)
1130                         .build()
1131                         .unwrap();
1132                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1133                 #[cfg(feature = "std")]
1134                 assert!(refund.is_expired());
1135                 assert!(refund.is_expired_no_std(now));
1136                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1137                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
1138         }
1139
1140         #[test]
1141         fn builds_refund_with_paths() {
1142                 let paths = vec![
1143                         BlindedPath {
1144                                 introduction_node_id: pubkey(40),
1145                                 blinding_point: pubkey(41),
1146                                 blinded_hops: vec![
1147                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1148                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1149                                 ],
1150                         },
1151                         BlindedPath {
1152                                 introduction_node_id: pubkey(40),
1153                                 blinding_point: pubkey(41),
1154                                 blinded_hops: vec![
1155                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1156                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1157                                 ],
1158                         },
1159                 ];
1160
1161                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1162                         .path(paths[0].clone())
1163                         .path(paths[1].clone())
1164                         .build()
1165                         .unwrap();
1166                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
1167                 assert_eq!(refund.paths(), paths.as_slice());
1168                 assert_eq!(refund.payer_id(), pubkey(42));
1169                 assert_ne!(pubkey(42), pubkey(44));
1170                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
1171                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
1172         }
1173
1174         #[test]
1175         fn builds_refund_with_issuer() {
1176                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1177                         .issuer("bar".into())
1178                         .build()
1179                         .unwrap();
1180                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1181                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1182                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
1183
1184                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1185                         .issuer("bar".into())
1186                         .issuer("baz".into())
1187                         .build()
1188                         .unwrap();
1189                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1190                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
1191                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
1192         }
1193
1194         #[test]
1195         fn builds_refund_with_chain() {
1196                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
1197                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
1198
1199                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1200                         .chain(Network::Bitcoin)
1201                         .build().unwrap();
1202                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1203                 assert_eq!(refund.chain(), mainnet);
1204                 assert_eq!(tlv_stream.chain, None);
1205
1206                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1207                         .chain(Network::Testnet)
1208                         .build().unwrap();
1209                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1210                 assert_eq!(refund.chain(), testnet);
1211                 assert_eq!(tlv_stream.chain, Some(&testnet));
1212
1213                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1214                         .chain(Network::Regtest)
1215                         .chain(Network::Testnet)
1216                         .build().unwrap();
1217                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1218                 assert_eq!(refund.chain(), testnet);
1219                 assert_eq!(tlv_stream.chain, Some(&testnet));
1220         }
1221
1222         #[test]
1223         fn builds_refund_with_quantity() {
1224                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1225                         .quantity(10)
1226                         .build().unwrap();
1227                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1228                 assert_eq!(refund.quantity(), Some(10));
1229                 assert_eq!(tlv_stream.quantity, Some(10));
1230
1231                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1232                         .quantity(10)
1233                         .quantity(1)
1234                         .build().unwrap();
1235                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1236                 assert_eq!(refund.quantity(), Some(1));
1237                 assert_eq!(tlv_stream.quantity, Some(1));
1238         }
1239
1240         #[test]
1241         fn builds_refund_with_payer_note() {
1242                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1243                         .payer_note("bar".into())
1244                         .build().unwrap();
1245                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1246                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
1247                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
1248
1249                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1250                         .payer_note("bar".into())
1251                         .payer_note("baz".into())
1252                         .build().unwrap();
1253                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1254                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1255                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
1256         }
1257
1258         #[test]
1259         fn fails_responding_with_unknown_required_features() {
1260                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1261                         .features_unchecked(InvoiceRequestFeatures::unknown())
1262                         .build().unwrap()
1263                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1264                 {
1265                         Ok(_) => panic!("expected error"),
1266                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1267                 }
1268         }
1269
1270         #[test]
1271         fn parses_refund_with_metadata() {
1272                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1273                         .build().unwrap();
1274                 if let Err(e) = refund.to_string().parse::<Refund>() {
1275                         panic!("error parsing refund: {:?}", e);
1276                 }
1277
1278                 let mut tlv_stream = refund.as_tlv_stream();
1279                 tlv_stream.0.metadata = None;
1280
1281                 match Refund::try_from(tlv_stream.to_bytes()) {
1282                         Ok(_) => panic!("expected error"),
1283                         Err(e) => {
1284                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerMetadata));
1285                         },
1286                 }
1287         }
1288
1289         #[test]
1290         fn parses_refund_with_description() {
1291                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1292                         .build().unwrap();
1293                 if let Err(e) = refund.to_string().parse::<Refund>() {
1294                         panic!("error parsing refund: {:?}", e);
1295                 }
1296
1297                 let mut tlv_stream = refund.as_tlv_stream();
1298                 tlv_stream.1.description = None;
1299
1300                 match Refund::try_from(tlv_stream.to_bytes()) {
1301                         Ok(_) => panic!("expected error"),
1302                         Err(e) => {
1303                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1304                         },
1305                 }
1306         }
1307
1308         #[test]
1309         fn parses_refund_with_amount() {
1310                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1311                         .build().unwrap();
1312                 if let Err(e) = refund.to_string().parse::<Refund>() {
1313                         panic!("error parsing refund: {:?}", e);
1314                 }
1315
1316                 let mut tlv_stream = refund.as_tlv_stream();
1317                 tlv_stream.2.amount = None;
1318
1319                 match Refund::try_from(tlv_stream.to_bytes()) {
1320                         Ok(_) => panic!("expected error"),
1321                         Err(e) => {
1322                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount));
1323                         },
1324                 }
1325
1326                 let mut tlv_stream = refund.as_tlv_stream();
1327                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
1328
1329                 match Refund::try_from(tlv_stream.to_bytes()) {
1330                         Ok(_) => panic!("expected error"),
1331                         Err(e) => {
1332                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount));
1333                         },
1334                 }
1335         }
1336
1337         #[test]
1338         fn parses_refund_with_payer_id() {
1339                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1340                         .build().unwrap();
1341                 if let Err(e) = refund.to_string().parse::<Refund>() {
1342                         panic!("error parsing refund: {:?}", e);
1343                 }
1344
1345                 let mut tlv_stream = refund.as_tlv_stream();
1346                 tlv_stream.2.payer_id = None;
1347
1348                 match Refund::try_from(tlv_stream.to_bytes()) {
1349                         Ok(_) => panic!("expected error"),
1350                         Err(e) => {
1351                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerId));
1352                         },
1353                 }
1354         }
1355
1356         #[test]
1357         fn parses_refund_with_optional_fields() {
1358                 let past_expiry = Duration::from_secs(0);
1359                 let paths = vec![
1360                         BlindedPath {
1361                                 introduction_node_id: pubkey(40),
1362                                 blinding_point: pubkey(41),
1363                                 blinded_hops: vec![
1364                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1365                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1366                                 ],
1367                         },
1368                         BlindedPath {
1369                                 introduction_node_id: pubkey(40),
1370                                 blinding_point: pubkey(41),
1371                                 blinded_hops: vec![
1372                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1373                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1374                                 ],
1375                         },
1376                 ];
1377
1378                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1379                         .absolute_expiry(past_expiry)
1380                         .issuer("bar".into())
1381                         .path(paths[0].clone())
1382                         .path(paths[1].clone())
1383                         .chain(Network::Testnet)
1384                         .features_unchecked(InvoiceRequestFeatures::unknown())
1385                         .quantity(10)
1386                         .payer_note("baz".into())
1387                         .build()
1388                         .unwrap();
1389                 match refund.to_string().parse::<Refund>() {
1390                         Ok(refund) => {
1391                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1392                                 #[cfg(feature = "std")]
1393                                 assert!(refund.is_expired());
1394                                 assert_eq!(refund.paths(), &paths[..]);
1395                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1396                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
1397                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
1398                                 assert_eq!(refund.quantity(), Some(10));
1399                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1400                         },
1401                         Err(e) => panic!("error parsing refund: {:?}", e),
1402                 }
1403         }
1404
1405         #[test]
1406         fn fails_parsing_refund_with_unexpected_fields() {
1407                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1408                         .build().unwrap();
1409                 if let Err(e) = refund.to_string().parse::<Refund>() {
1410                         panic!("error parsing refund: {:?}", e);
1411                 }
1412
1413                 let metadata = vec![42; 32];
1414                 let mut tlv_stream = refund.as_tlv_stream();
1415                 tlv_stream.1.metadata = Some(&metadata);
1416
1417                 match Refund::try_from(tlv_stream.to_bytes()) {
1418                         Ok(_) => panic!("expected error"),
1419                         Err(e) => {
1420                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedMetadata));
1421                         },
1422                 }
1423
1424                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
1425                 let mut tlv_stream = refund.as_tlv_stream();
1426                 tlv_stream.1.chains = Some(&chains);
1427
1428                 match Refund::try_from(tlv_stream.to_bytes()) {
1429                         Ok(_) => panic!("expected error"),
1430                         Err(e) => {
1431                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedChain));
1432                         },
1433                 }
1434
1435                 let mut tlv_stream = refund.as_tlv_stream();
1436                 tlv_stream.1.currency = Some(&b"USD");
1437                 tlv_stream.1.amount = Some(1000);
1438
1439                 match Refund::try_from(tlv_stream.to_bytes()) {
1440                         Ok(_) => panic!("expected error"),
1441                         Err(e) => {
1442                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedAmount));
1443                         },
1444                 }
1445
1446                 let features = OfferFeatures::unknown();
1447                 let mut tlv_stream = refund.as_tlv_stream();
1448                 tlv_stream.1.features = Some(&features);
1449
1450                 match Refund::try_from(tlv_stream.to_bytes()) {
1451                         Ok(_) => panic!("expected error"),
1452                         Err(e) => {
1453                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedFeatures));
1454                         },
1455                 }
1456
1457                 let mut tlv_stream = refund.as_tlv_stream();
1458                 tlv_stream.1.quantity_max = Some(10);
1459
1460                 match Refund::try_from(tlv_stream.to_bytes()) {
1461                         Ok(_) => panic!("expected error"),
1462                         Err(e) => {
1463                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedQuantity));
1464                         },
1465                 }
1466
1467                 let node_id = payer_pubkey();
1468                 let mut tlv_stream = refund.as_tlv_stream();
1469                 tlv_stream.1.node_id = Some(&node_id);
1470
1471                 match Refund::try_from(tlv_stream.to_bytes()) {
1472                         Ok(_) => panic!("expected error"),
1473                         Err(e) => {
1474                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedSigningPubkey));
1475                         },
1476                 }
1477         }
1478
1479         #[test]
1480         fn fails_parsing_refund_with_extra_tlv_records() {
1481                 let secp_ctx = Secp256k1::new();
1482                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
1483                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
1484                         .build().unwrap();
1485
1486                 let mut encoded_refund = Vec::new();
1487                 refund.write(&mut encoded_refund).unwrap();
1488                 BigSize(1002).write(&mut encoded_refund).unwrap();
1489                 BigSize(32).write(&mut encoded_refund).unwrap();
1490                 [42u8; 32].write(&mut encoded_refund).unwrap();
1491
1492                 match Refund::try_from(encoded_refund) {
1493                         Ok(_) => panic!("expected error"),
1494                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1495                 }
1496         }
1497 }